Resistor



Patented Jan. 4, 1944 UNITED RESISTOR Edward J. Naumann, Baltimore, and John E.

Gilhooly, Catonsville, Md., assignors to Westlnghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application May 2, 1942, Serial No. 441,502

(Cl. 20L- 63) 3 Claims.

Our invention relates generally to resistors, and has reference in particular to resistors adapted for forced cooling.

Generally stated, it is an object of our invention to provide an improved design of resistor which is simple and inexpensive to manufacture and which is durable in use.

More specically, it is an object of our invention to provide a non-inductive resistance element wherein the resistor forms a conduit for a cooling uid.

Another object of our invention is to provide a coated resistance element which is not easily damaged in handling.

Yet another object of our invention is to provide a non-inductive resistance element having a hollow support oi insulating material with a coating of resistance material on the inner surface thereof.

It is also an object of our invention to provide for utilizing the end members of a hollow iiuid cooled resistor as the resistor terminals.

- Still another object of our invention is to provide a non-inductive iluid cooled resistor of simple construction which has a substantially permanent calibration.

Other objects will in part be obvious and will in part be explained hereinafter.

In practicing our invention, a non-inductive resistor may be provided by depositing a conductive resistance coating on the inner surface of a hollow insulating support. End members substantially enclosing the ends of the support may be provided with openings therethrough to serve as inlet and outlet passages for circulating a cooling fluid such as air, water, or the like through the support in contact with the coating. The end members may also be utilized as resistor terminals by connecting them to a highly conductive metallic coating applied to the resistance coating adjacent the ends of the support.

For a more complete understanding of the nature and scope of our invention, reference may be had to the following detailed description which may be read in connection with the accompanying drawing, in which the single ilgure represents a side elevational view, partly in section, of a resistor embodying the principal features of the invention. v

Referring to the drawing, the reference numeral I may denote, generally, a non-inductive resistor comprising, an insulating support Il having a resistance coating l2 applied thereto and provided with end members denoted generally by the numeral Il.

In order to provide a relatively simple and inexpensive resistor which may be easily manufactured and have a substantially permanent calibration, the support may be provided with an elongated opening i3 therethrough, and the resistance coating i2 applied to the interior sur- 'iace of the opening. The support il may be made of any suitable insulating material comprising, for example, a tube of any one of the many synthetic resins, or of glass, porcelain or another of the refractory materials. The resistance coating I2 may comprise any material such as iinely divided particles 0f aluminum or other metal which may be 'applied by spraying to the interior of the support ii, or finely divided particles of a carbonaceous material, such as carbon black or graphite with a suitable binder such `as a synthetic resin which may be either applied to the interior surface oi the support Il by spraying. painting, dipping or the like.

In order to provide for cooling the resistor i0, the end members I4 may comprise enlarged head portions I5 which substantially enclose the ends of the support Il, and stem portions I 6 havingl openings l1 therethrough communicating with the interior of the support Il. Inlet and outlet ports may thus be provided for a cooling fluid such as water, oil, air, or a neutral gas.

The end members I4 may be secured to the support member Ii in any suitable manner. In order to utilize the end members as resistor terminals, provision may be made for electrically connecting the end members to the resistance coating i2. For example, a relatively highly conductive coating I9 of copper, or aluminum, or the like, may be applied to the resistance coating l2 adjacent the ends oi the support Il, and the head portion i5 of the end members may be connected thereto by providing a driving nt, or means such as the solder seal 20. Electrical connection to the resistance coating i2 may then be' made by means of conductors 22 connected Ato the end members by terminal members 23 and nuts 24.

From the above description and the accompanying drawing, it will be apparent that we have provided a non-inductive resistor of relatively simple construction which is inexpensive to manufacture. By utilizing the hollow support as a conduit for a cooling fluid, which may flow directly in contact with the resistance coating, a highly eiiicient resistor of relatively simple construction is provided. Damage to the resistance coating is prevented, since the coating is applied to the inside of the support whereby it is effectively protected. The calibration or the resistor is thereby made much more permanent, since the resistance coating is not only protected against mechanical injury, but is also protected against contact with injurious gases which might cause oxidation or corrosion of the resistance coating to change its resistance value.

Since certain changes may be made in the above description, and dinerent embodiments of' the invention may be made without departing from the spirit thereof, it is intended that all the matter contained in the above description and shown in the accompanying drawing shall be considered as illustrative and not in a limiting sense.

We claim as our invention: f

1. A resistor comprising an elongated support of insulating material having a longitudinal opening therethrough to provide an inner surface, a conductive coating applied to the inner surface of the support, and end members enclosing the ends of the support provided with openings for circulating a cooling fluid over the coating.

2. A uid cooled resistor comprising, a tubular insulating support having a coating or resistance material on its inner surface, a metallic coating of relatively high conductivity superimposed on the said conductive coating adjacent the ends of the support, and terminal members enclosing the ends of the support having head portions positionedwithin and engaging the metallic coating, said terminal members being provided with axially projecting terminal studs having opening for circulating a cooling fluid through the support.

3. A resistor comprising, a refractory tubular support, a carbonaceous resistance coating extending along the inner surface of the support, a metallic coating superimposed on the carbonaceous coating adjacent the ends of the support, and metallic end plugs substantially enclosing the ends of the support provided with inlet and outlet ports to pass a cooling fluid through the support, said end plugs engaging the metallic coating to provide terminals for the coating.

JOHN E. GILHOOLY. EDWARD J. NAUMANN. 

